A hash algorithm is a function which takes a variable size input and produces a fixed size output. The algorithm tries to make it difficult to predict the output for a given input, find two inputs with the same output, or reconstruct the input from the output.

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2answers
35 views

How to brute force this token in php, if it is possible

it is possible to brute-force this token (MD5 Hash) of the following script (PHP) in a realistic time (0,5h - 24h)? If the answer is YES, how could I do it, for example with PHP or Python? $time = ...
2
votes
0answers
12 views

hash function notations and existing cryptographic hash algorithms [migrated]

I am implementing Role-based access control by referencing the paper Enforcing Role-Based Access Control for Secure Data Storage in the Cloud. In page 6, they have mentioned to choose hash functions ...
-1
votes
4answers
54 views

How are salts safe in the database? [duplicate]

I have read many and many of this type of question on the security stack community before I asked this question, but one thing that made me mad about salts and saving it in database is this ... I will ...
10
votes
4answers
8k views

HMACSHA512 versus Rfc2898DeriveBytes for password hash

We are currently using HMACSHA512 in .net, with a 128Char (64byte) validation key The salt is 64 char randomly generated string. We allocated 2048 length on the database for the hashed base64 string ...
2
votes
0answers
24 views

Recommended Crypto Security Setup (Implemented Algorithms)?

Firstly I'm not a crypto expert, however I know how to use algorithms that other people have defined before in practical usages, that is, as long as they live up to their promises. The thing is that ...
4
votes
2answers
559 views

Keepass Dictionary Attack Protection Strategy

Though pretty interested, I'm everything but an expert in Information Security, please redirect me to any helpful resources if my question is stupid or correct me if my assumptions are wrong. When ...
72
votes
13answers
6k views

VP of IT claims he unhashed 100% of all 16k employees' PWs. Is he lying to us?

I work for a company which has ~16,000 employees. Periodically, our VP of IT sends out a newsletter with "tech-tips" and misc IT stuff. The topic of this week's newsletter was "password security". ...
2
votes
0answers
86 views

Any vulnerability in .net implementation for C# object.GetHashCode?

I've already asked this question on SO, but I think that this forum is more appropriate to discuss security issues. My point is that most OO languages has a way to get a unique hash code for an ...
1
vote
2answers
48 views

Does a hash of a 32-bit integer make a better hash salt than the integer itself?

I have a scenario where I already have a table of resource passwords stored as unsalted 128-bit hashes. I'm unable to force owners to provide new passwords, so I'm trying to mitigate the situation by ...
26
votes
2answers
2k views

How can the content of a file refer to its own MD5?

So I just saw this picture on Imgur: http://imgur.com/gxRCrCM The intriguing thing about it is that the picture refers to an old Daft Punk song named "Face 2 Face". The image's MD5 is ...
0
votes
2answers
96 views

How secure is the hashing/salting/stretching process as described in this diagram?

Question I was just brainstorming about the hashing, stretching, salting part of the user password in the authentication process and I want it to be as secure as possible (no matter how paranoid that ...
7
votes
1answer
118 views

What are the recommended scrypt cost factors for 2016?

I've been trying to look for the answer, but the latest one I found was outdated by three years. So what are the recommended scrypt cost factors for 2016?
1
vote
1answer
59 views

How secure is the UNIX sha_crypt as a password storage algorithm? [duplicate]

So I have been working on password storage, especially on the algorithms to use (and to not use). Most people are recommending scrypt or PBKDF2 for valuable reasons, but I have not seen any talks ...
-1
votes
2answers
133 views

How long would it take to generate a file to match a hash? [duplicate]

A individual file only has a single hash of any specific byte length. But an individual hash can represent a large number of different files. Given a 256 byte hash, how long would it take to ...
-6
votes
1answer
86 views

How to detect if a crack is cracked only or cracked and binded with other executable? [closed]

Viruses are often spread using cracks. I want a quick and dirty way to know if the cracks are not binded with other executables The process goes like this. The program is installed using the ...
-1
votes
2answers
72 views

Website says my new password can't be used because it is the same as an old one [duplicate]

What are the risks of storing (in hashes I guess) all the old passwords? Why would a company chose to not delete old passwords? Why not let users reuse old passwords?
123
votes
6answers
46k views

Password Hashing add salt + pepper or is salt enough?

Please Note: I'm aware that the proper method for secure password storage hashing is either scrypt or bcrypt. This question isn't for implementation in actual software, it's for my own understanding. ...
7
votes
2answers
161 views

Is there any recommended approach for “upgrading” MD5 hashes to something secure? [duplicate]

I'm currently dealing with a couple of user accounts containing MD5 hashed passwords. These accounts got migrated from an old system into our current system which uses PBKDF2 for password hashing. I ...
1
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3answers
282 views

About SHA1 in default Disk Encryption in Linux

Link to the thread: Recommended options for LUKS (cryptsetup) I wonder what's the exact difference between SHA1 and SHA512. I know that SHA512 has a longer key but I've read that it doesn't matter ...
-5
votes
0answers
75 views

How can I decode hashed passwords? [duplicate]

I have access to a Microsoft SQL database where passwords are stored like this: bZB056KMVxCXa/D8zd3q/g== How can I decrypt this hash? I don't know which algorithm is used for this hash.
27
votes
3answers
4k views

Can I share what password hash function I used in a public report?

I have developed a web site during an internship, using a database with accounts. I used the crypt() method from PHP, with a secured algorithm plus salt (found on the web with a lot of feedback). ...
20
votes
4answers
18k views

Whats the difference between MAC vs hash

What is the difference between the two algorithms? One difference that I know of, is that MAC is keyed and hash is not.
0
votes
0answers
26 views

ISO 9564 Approved Encryption Algorithms for PIN, why symmetric block ciphers?

I am currently researching best practices in designing a potential PIN management solution for a financial services application and began looking into ISO 9564 as a source of requirements. One of the ...
7
votes
3answers
16k views

Generating an unguessable token for confirmation e-mails

I'm generating a token to be used when clicking on the link in a verification e-mail. I plan on using uniqid() but the output will be predictable allowing an attacker to bypass the confirmation e-...
2
votes
1answer
114 views

PHP BLENC extension security concern

PHP BLENC is a extension that allows PHP developer encrypt their code, protect their ideas and avoid illegal copy. Although BLENC allow developer to define the main encryption key in source(in the ...
1
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1answer
64 views

Firmware protection scheme

Edit: I have found a scheme that fits my limits (little memory, only AES is available): AES-CMAC described in RFC 4493 (just remember to use different key for encryption and MAC ;) . I am working ...
1
vote
1answer
139 views

Which file encryption algorithm is used by Synology's Cloud Sync feature? [closed]

I'm trying to find out which encryption method is used by a piece of software I use, viz. the 'Cloud Sync' feature of Synology's DSM 6.0 running on a Synology NAS. (Background. This Cloud Sync ...
1
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1answer
82 views

Multi hash security [duplicate]

Is md5(sha1(pass)) more secure than md5(pass)? For example in case of sqli when an attacker can't get our hashing schema, brute force or dictionary attack would be much less efficient. Am I right or ...
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votes
1answer
129 views

Where do webstites store the hashes? [closed]

I understand that lots of websites store passwords in hashes but where do they actually store the hashes? How can a website compare your hashed version of a password with theirs? Is it stored ...
1
vote
1answer
73 views

Is using dynamic obfuscation and peppers for password hashing a good idea?

I've read now the whole day about password hashing and secure authentication and though I read very often that mostly every own algorithm makes the proven hashing methods just less secure, I just got ...
4
votes
1answer
99 views

Is it possible to use parallelism when computing a key derivation function for a single password/key?

Suppose I have an AES-256 encrypted file, and I want to derive the key using PBKDF2 and a given salt with a large number of rounds (say 1 million), but I'm limited by user tolerance for UI lag when ...
1
vote
1answer
88 views

Password Encryption For PHP 5.3 or Should We Update to 5.5+?

I'm trying to hash passwords for our company site. After testing on a local Apache server that has PHP 5.5.9 and everything working as expected, I went to test on our live server being hosted by ...
1
vote
3answers
260 views

why don't we store passwords in a database using encryption instead of hashing? [duplicate]

hashing is a one way method, if a user lost his password he will never be able to get that password from the server, so why don't we store passwords in a database using encryption instead of hashing?
0
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0answers
36 views

How to extract the hash from SMB

I have a running PC which I need to test against.It is running Windows with SMB enabled. When capturing using Wireshark while connecting with an incorrect password I see packets being sent to / from ...
0
votes
1answer
32 views

If domain admin account's NTLM hash is compromised, can it be used to access any machine in network

If a hacker able to get local admin rights and then from there local domain admin's NTLM hash. Can he use this hash without cracking, to access shared folders in the network and the default C drive ...
13
votes
1answer
568 views

Naive implementation of Rainbow Table and/or Hellman's trade-off

This question is the same one I asked here. Since I haven't got any response or even a comment I will post it here as well. Is there any naive implementation of Hellman's cryptanalytic time memory ...
-1
votes
2answers
104 views

Secure password generation for different websites [duplicate]

I came up with the idea to generate passwords for internet sites by the following shema: $masterpassword $hostname $TLD hashfunction($TDL.$masterpassword.$hostname) So the actual password is a ...
2
votes
1answer
225 views

Encrypting data before sending to SaaS tool and decrypting on browser view

I'd like to send data to a SaaS tool, where the data is stored in the cloud. I'll use Google Analytics as an example, but it applies to any similar service. Google Analytics does not allow you to ...
-3
votes
2answers
94 views

Will hashing a password, and then splitting it into multiple db fields increase security? [duplicate]

I've been reading up on Password hashing, and it seems like there is a lot of opinions on "What's right." I'm curious about the possibility of storing a split of a Hashed password in multiple user ...
34
votes
5answers
5k views

Should I trust a website which uses a SHA-1 HTTPS certificate?

I am on a website where I need to pay for something. This website has the following warning in the top left: This site uses a weak security configuration (SHA-1 signatures) so your connection ...
4
votes
1answer
267 views

OpenSSL 0.9.6a PRNG algorithm weakness: How to exploit?

I saw an OpenSSL security advisory for Openssl 0.9.6a Recently a cryptographic flaw in OpenSSL's built-in pseudo-random number generator (PRNG) was pointed out to us by Markku-Juhani O. Saarinen <...
1
vote
0answers
6 views

Calculating probability of finding collisions in an invertible hash function [migrated]

Assuming we have an invertible hash function H that takes inputs of size 2n and outputs hashes of size n, I use the following algorithm to find collisions: Choose a random M as input. Compute its ...
1
vote
1answer
109 views

How to implement iterations when hashing passwords?

To securely hash passwords, algorithms such as PBKDF2 do many iterations of a common hash such as SHA1. Are there certain ways that these iterations need to be done to be safe? In particular, from ...
59
votes
3answers
43k views

Securing a JavaScript Single Page App with RESTful backend

I'm currently in the process of building a JavaScript SPA and have been researching how to secure it. There is currently as RESTful API that is being completely interacted with through AJAX. We also ...
0
votes
0answers
17 views

Securing FTP Creds in a Java Open Source API

I've written a basic Java API and source code must be released to a small community for the application to function correctly. The Java API helps developers track data for their running scripts and ...
0
votes
1answer
74 views

Possible to take hash from know result and algorithm?

I am trying to build a casino site in PHP where users can play roulette. I found this algorithm that I want to use to "roll" numbers: <?php $secret = '...
0
votes
2answers
147 views

store passwords as one-way-hash, or just use it as an AES key?

I want to store some data so the only one who'll be able to access it is the user itself. Here is my idea: when user registers, his password will be hashed in SHA256 (so it'll fit as an AES key), and ...